The neighborhood we’re raised in shapes the brain
STUDY: Marek S et al, bioRxiv 2025
STUDY TYPE: Cross-sectional neuroimaging study
FUNDING: National Institutes of Health; additional federal partners through the Adolescent Brain Cognitive Development (ABCD) Study
Background
Why do some brains look different than others? Early research has pinned it on psychiatric disorders or IQ, but this new study finds that socioeconomic status leaves a bigger mark than either of those.
The Study
- Nearly 5,000 children ages 9-10 in the Adolescent Brain Cognitive Development (ABCD) Study.
- Researchers mapped 649 variables (socioeconomics, cognition, mental health, screen time, sleep, etc) onto brain connectivity and cortical thickness using MRI.
- Findings were replicated in a separate ABCD sample and in 32,572 adults from the UK Biobank.
Of the top 40 variables most strongly associated with brain connectivity, 37 were socioeconomic. IQ ranked 59th. Psychopathology ranked lower still. A single “exposome” brain pattern, anchored in sensory and motor cortex, captured 34% of the variance across all 649 variables, and it looked nearly identical to the socioeconomic brain map. Sleep and screen time tracked closely with it too.
When researchers adjusted brain-IQ associations for socioeconomic status, 95% weakened and about 70% lost statistical significance. Brain-IQ models trained only on children from higher socioeconomic backgrounds failed to generalize: their out-of-sample correlation dropped to essentially zero. Brain-socioeconomic status models held up regardless of IQ range, genetic ancestry, or sex.
Stress and sleep may be driving the difference. The brain pattern tied to socioeconomic status overlapped with sleep EEG signatures, norepinephrine receptor density, and stimulant drug effects, not with prefrontal activation during complex cognition. These brain regions are shaped by stress, sleep, and screen time.
Limitations
Cross-sectional by design, and cannot establish causation.
Practice Implications
- When a child struggles with ADHD, insomnia, or emotional regulation, neighborhood poverty may be shaping the brain more than IQ or any diagnosis.
- Sleep and chronic stress are the leading candidates for intervention. Greenspace is also limited in poor neighborhoods, and previous research has linked that to cognitive problems. Ask about all of these. They may inform the treatment plan, but are not an excuse to withhold treatment.
- The findings suggest we’ll need to rethink earlier studies linking cognitive performance to brain differences that did not control for poverty.
—Chris Aiken, MD
Director, Psych Partners
Editor in Chief, Carlat Psychiatry Report
